The objective of this research is to determine the effects of selected dietary states on the function of drug metabolizing enzymes of rat liver, lung and perhaps intestinal mucosa. Changes in either rate of metabolism or the metabolic pathway of benzo(a)pyrene 2-acetylaminofluorene or dimethylnitrosamine will be evaluated with the potential to induce reverse mutations in histidine dependent S. typhimurium. Verification of mutagenicity as a measure of carcinogenicity will be further correlated with the characteristics of binding of metabolites to calf thymus deoxyribonucleic acid. Diets deficient in or supplemented with essential fatty acids or thiamin will be fed for one to three weeks. Metabolism of carcinogen will be assessed using an in vitro microsomal system containing necessary co-factors or isolated perfused liver. Mutagenicity will be assessed using the bacterial mutagenicity method developed by Ames. Various metabolites will be extracted from incubation or perfusion mixture using thin layer, high pressure liquid and/or gas liquid chromatography.